Intel Multibus
Computer Bus Architecture
developed in the 1970s

General description

The main points about the Intel Multibus architecture:

  • Versatile Application: Multibus was adaptable for industrial and embedded systems.
  • Modular Design: It allowed easy addition and removal of peripherals.
  • Parallel Communication: Multibus used parallel lines for faster data transfers.
  • Simplified Setup: Daisy-chaining reduced physical complexity.
  • Open Specifications: Shared specs encouraged compatibility among manufacturers.
  • Industrial Focus: It excelled in robust industrial applications.

Intel Multibus, also known as Intel Multibus I, was an early computer bus architecture developed by Intel in the 1970s. A bus architecture refers to a set of specifications and standards that define how different components of a computer system communicate with each other.

Intel Multibus was designed as a versatile and extensible bus system primarily intended for use in industrial and embedded systems. It allowed different hardware components, such as CPUs, memory modules, I/O devices, and other peripherals, to communicate and exchange data within a computer system. The architecture supported both 8-bit and 16-bit data paths.

Key features and characteristics of Intel Multibus include:

  1. Versatility: The Multibus architecture was designed to be adaptable and suitable for a wide range of applications, from industrial automation to scientific equipment.
  2. Modularity: It allowed for the easy addition or removal of peripheral devices and expansion cards, making it well-suited for systems with changing requirements.
  3. Parallel Communication: Intel Multibus utilized parallel communication lines for data, address, and control signals, allowing for relatively high data transfer rates compared to other contemporary bus systems.
  4. Daisy-Chaining: Multibus allowed devices to be daisy-chained, where multiple devices could be connected along the same bus, simplifying the overall system layout.
  5. Backward Compatibility: Intel Multibus was designed to be compatible with earlier bus standards like the S-100 bus, allowing some level of compatibility with existing hardware and software.
  6. Open Architecture: The specifications for Intel Multibus were publicly available, allowing other manufacturers to develop compatible hardware and peripherals.

Despite its advantages, Intel Multibus I had limitations such as being relatively complex to implement and lacking a standardized memory-mapped I/O architecture. As a result, it faced competition from other bus architectures, and newer bus standards like the VMEbus gained popularity in the later years.

It’s important to note that Intel Multibus I is distinct from the later Intel Multibus II, which was an improved version of the original architecture with enhanced features and capabilities. Multibus II was used in various applications, including industrial automation and military systems.

Overall, while Intel Multibus I is not widely used today due to its age and the evolution of bus architectures, it played a role in the early development of computer systems and had an impact on subsequent bus standards.


Intel Multibus Examples

Intel Multibus was utilized in a variety of applications during its prime, particularly in the late 1970s and early 1980s. Here are a few examples of where you might have encountered Intel Multibus architecture:
  1. Intel MDS Series: The Intel MDS (Microcomputer Development System) series, including models like MDS-800 and MDS-225, used Intel Multibus architecture. These systems were used for software development and testing.
  2. Intel Intellec Prompt Series: The Intel Intellec PROMPT 80/85 series of microcomputer development systems, employed Multibus iSBC-80/10B for hardware and software development purposes.
  3. Scientific Measurement Systems: Many scientific measurement and data acquisition systems in laboratories used Intel Multibus for its parallel communication capabilities and real-time processing.
  4. Industrial Control Systems: Multibus was integrated into industrial control systems for automating manufacturing processes and managing machinery.
  5. Medical Equipment: Some early medical equipment, such as diagnostic devices and monitoring systems, employed Intel Multibus for data processing and control.
  6. Telecommunication Switches: Certain telecommunication switches and equipment used Multibus for handling signal processing and communication tasks.

The Intel Multibus boards in my collection:

Intel Single Board Computer

Intel Flexible Diskette Controllers

  • Intel iSBC 204
  • Intel iSBC 208

Intel Hard Disk Controllers